If one of the (four) strings were cut off and there is at least 2 inches left, it is still kosher. So too, even if 2 (of the four) strings got cut off, it will still be kosher as long as there is 2 inches left of each one. However, if 3 or more strings got cut off then it is pasul and you must take them off. Additionally, if one of the strings were cut near the hole of the garment, it is pasul.